Transflective Liquid Crystal Display Device

ABSTRACT

In a transmissive mode, the light emitted from a backlight ( 11 ) in reflective region B passes through a circularly polarized light plate ( 13 ). The light passed through the circularly polarized light plate ( 13 ) becomes the right circularly polarized light by the absorption of a part of the left circularly polarized light by the absorption of a part of the left circularly polarized light, If the right circularly polarized light launches into a retardation film ( 12   e ) of a liquid crystal panel ( 12 ), a phase of the light delays with λ/4. The light delayed with λ/4 becomes the linearly polarized light and is reflected on a reflective film ( 12   d ). The light reflected on the reflective film ( 12   d ) delays its phase with λ/4 by the retardation film ( 12   e ). Therefore, the right circularly polarized light, passed through the retardation film ( 12   e ) again, returns to the right circularly polarized light. The right circularly polarized light passes through the circularly polarized light plate ( 13 ) as the right circularly polarized light plate, reflects on a reflective film ( 11   b ) of the backlight ( 11 ), and is diffused by a diffusing film ( 11   a ). The right circularly polarized light returns to the natural light as well as the light from the backlight ( 11 ) with a circularly polarized state canceled when passing through the diffusing film ( 11   a ). The light reflected on the backlight ( 11 ) adds to the light emitted directly from the backlight ( 11 ) in a transmissive region A.

TECHNICAL FIELD

The present invention relates to a transflective liquid crystal displaydevice, in particular to a transflective liquid crystal display deviceusing the light from a backlight efficiently.

BACKGROUND ART

A so-called transflective liquid crystal display device, which reflectsambient light incident from a front side, leads the reflected light tothe front side and at the same time allows incident light from abacklight system on the back to pass therethrough so as to be led to thesame front side, is becoming commercialized with reality. This type ofliquid crystal display device displays images effectively usingprincipally ambient light when an operating environment is bright(reflective mode) and principally spontaneous light of the backlightsystem (transmissive mode) when the operating environment is dark.

Prior art documents US2001/0017679 and US2002/0089623 disclose this typeof liquid crystal display device.

Here, a conventional transflective liquid crystal display device will beexplained using FIG. 1. FIG. 1 is a sectional view diagrammaticallyshowing an arrangement of a conventional transflective liquid crystaldisplay device.

The transflective liquid crystal display device in FIG. 1 is principallyconstructed of a backlight 1 used in a transmissive mode, a liquidcrystal panel 2 arranged above this backlight 1 and a pair of circularlypolarized light plates 3, 4 arranged to sandwich this liquid crystalpanel 2.

The backlight 1 is constructed of a light guide plate 1 c which guideslight and a light source (not shown) arranged at an end of the lightguide plate 1 c. A diffusing film 1 a which diffuses light emitted ontothe liquid crystal panel 2 through the light guide plate 1 c is formedon the surface of the light guide plate 1 c on a side of the liquidcrystal panel 2 and a reflective film 1 b which reflects light from thelight source is formed on the surface opposite to the surface of thelight guide plate 1 c on a side of the liquid crystal panel 2.

The liquid crystal panel 2 includes a pair of glass substrates 2 a, 2 b,a liquid crystal layer 2 c sandwiched therebetween, a stepwise member 2e provided on a reflective region B on the glass substrate 2 a and areflective film 2 d formed on the stepwise member 2 e.

Pixels are formed on the glass substrate 2 a and each pixel is providedwith the reflective region B having the reflective film 2 d and thetransmissive region A (region without any reflective film) having anopening for allowing light from the backlight 1 to pass therethrough. Ineach pixel, the reflective region B is formed to surround thetransmissive region A.

The liquid crystal panel 2 has electrodes, a color filter, anorientation film which controls the orientation of liquid crystalmolecules, but explanations thereof will be omitted here for simplicityof explanation.

The circularly polarized light plates 3, 4 are circularly polarizedlight plates having polarization directions opposite to each other.Here, suppose the circularly polarized light plate 3 is a rightcircularly polarized light plate and the circularly polarized lightplate 4 is a left circularly polarized light plate.

In the transflective liquid crystal display device in the abovedescribed structure, when the light from the backlight 1 is used as alight source in a transmissive mode, the light emitted from thebacklight 1 passes through the circularly polarized light plate 3 in thereflective region B. Since the circularly polarized light plate 3 is aright circularly polarized light plate, a part of the left circularlypolarized light of the light which has passed through the circularlypolarized light plate 3 is absorbed and becomes the right circularlypolarized light.

This right circularly polarized light is reflected on the reflectivefilm 2 d. The light reflected on the reflective film 2 d is changed fromthe right circularly polarized light to the left circularly polarizedlight. When this left circularly polarized light returns to thecircularly polarized light plate 3, the left circularly polarized lightis absorbed by the circularly polarized light plate 3 and cannot passthrough the circularly polarized light plate 3 because the circularlypolarized light plate 3 is a right circularly polarized light plate.

As described above, in the transflective liquid crystal display device,each pixel has a reflective region and a transmissive region. Since thereflective region is normally wider than the transmissive region, whenthe light from the backlight 1 is reflected on the reflective film 2 das shown above and the light from the backlight 1 is consequentiallyabsorbed by the circularly polarized light plate 3, a great portion ofthe backlight 1 is not fully used in a transmissive mode.

DISCLOSURE

It is an object of the present invention to provide a transflectiveliquid crystal display device which is able to use the light from abacklight efficiently in a transmissive mode.

The transflective liquid crystal display device according to the presentinvention has a liquid crystal panel in which liquid crystal material issealed between a pair of substrates faced with each other and in whichpixels formed on one substrate of the pair of substrates havetransmissive regions and reflective regions, comprising a pair ofcircularly polarized light members arranged outside the liquid crystalpanel and a backlight arranged outside one circularly polarized lightmember of the pair of circularly polarized light members, wherein thereflective region has a reflective member for reflecting ambient lightfrom an opposite side of backlight-arranging side in the liquid crystalpanel, and the reflective region has phase difference forming meansarranged on the backlight-arranging side of the reflective member.

This structure allows the phase difference forming means to reverse thepolarization direction of the circularly polarized light from thebacklight in the reflective region. This allows the light reflected onthe reflective member to pass through the circularly polarized lightmember. Therefore, the light from the backlight in the reflective regionwhich conventionally used to be wasted without being used can be used ina transmissive mode.

In the transflective liquid crystal display device according to thepresent invention, the phase difference forming means preferably has afunction of reversing a direction of circularly polarized light byallowing circularly polarized light to pass therethrough twice.

In an embodiment of the transflective liquid crystal display deviceaccording to the present invention, the phase difference forming meansis formed on the reflective regions in a main surface inside the liquidcrystal panel on one substrate on the backlight-arranging side of a pairof substrates and the reflective member is formed on the phasedifference forming means. In this case, the phase difference formingmeans is preferably a retardation film for delaying phase with λ/4.Furthermore, the phase difference forming means also serves as astepwise member for adjusting a balance between transmittance in thetransmissive region and reflectance in the reflective region.

In another embodiment of the transflective liquid crystal display deviceaccording to the present invention, the phase difference forming meansis orientation-processed polymer liquid crystal layer. In this case, thepolymer liquid crystal layer preferably delays phase with λ/4.

In a further embodiment of the transflective liquid crystal displaydevice according to the present invention, the phase difference formingmeans is formed on the reflective regions in a main surface outside theliquid crystal panel on one substrate on the backlight-arranging side ofa pair of substrates. In this case, the phase difference forming meansis preferably a retardation film or a phase difference film for delayingphase with λ/4.

DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view diagrammatically showing an arrangement of aconventional transflective liquid crystal display device;

FIG. 2 is a sectional view diagrammatically showing an arrangement of atransflective liquid crystal display device according to an Embodiment 1of the present invention;

FIG. 3 a is a sectional view showing another example of phase differenceforming means in a transflective liquid crystal display device accordingto an Embodiment 2 of the present invention; and

FIG. 3 b is a sectional view showing another example of phase differenceforming means in a transflective liquid crystal display device accordingto an Embodiment 3 of the present invention.

BEST MODE

With reference now to the attached drawings, embodiments of the presentinvention will be explained in detail below.

Embodiment 1

FIG. 2 is a sectional view diagrammatically showing an arrangement of atransflective liquid crystal display device according to an Embodiment 1of the present invention. In FIG. 2, the transflective liquid crystaldisplay device actually includes electronic devices and optical devicessuch as electrodes, a color filter, an orientation film, butexplanations thereof will be omitted here for simplicity of explanation.

The transflective liquid crystal display device in FIG. 2 areprincipally constructed of a backlight 11 used in a transmissive mode, aliquid crystal panel 12 arranged above this backlight 11 and a pair ofcircularly polarized light plates 13, 14 arranged to sandwich thisliquid crystal panel 12.

The backlight 11 is constructed of a light guide plate 11 c and a lightsource (not shown) arranged at an end of the light guide plate 11 c. Adiffusing film 11 a which diffuses light emitted onto the liquid crystalpanel 12 through the light guide plate 11 c is provided on the surfaceof the light guide plate 11 c on a side of the liquid crystal panel 12and a reflective film 11 b which reflects light from the light source isprovided on the surface opposite to the surface of the light guide plate11 c on a side of the liquid crystal panel 12.

In the backlight 11 with the above-mentioned structure, the lightemitted from the light source enters the light guide plate 11 c, isreflected on the reflective film 11 b of the light guide plate 1 c anddirected toward the liquid crystal panel 12 (upward in FIG. 2). Thislight is diffused by the diffusing film 11 a of the light guide plate 11c and used as the light of the backlight 11 in a transmissive mode.

An LED (light-emitting diode), etc., can be used as the light source.Furthermore, a metal film such as an aluminum film can be used as thereflective film 11 b. Furthermore, a polycarbonate film containingdiffusing grains, etc., can be used as the diffusing film 11 a.

The liquid crystal panel 12 includes a pair of glass substrates 12 a, 12b, a liquid crystal layer 12 c sandwiched therebetween, a retardationfilm 12 e which is phase difference forming means provided in areflective region B on the glass substrate 12 a and a reflective film 12d formed on the retardation film 12 e. This retardation film 12 e has afunction of delaying phase with, for example, ¼ (approximately 100 to200 nm). A resin material such as polycarbonate can be used as thematerial of the retardation film 12 e.

Pixels are formed on the glass substrate 12 a and each pixel is providedwith the reflective region B having the reflective film 12 d and thetransmissive region A (region without any reflective film) having anopening for allowing the light from the backlight 11 to passtherethrough. In the respective pixels, the reflective region B isformed to surround the transmissive region A.

When the reflective region B and transmissive region A are formed usingthe retardation film 12 e, the retardation film 12 e is formed on theglass substrate 12 a first.

For example, the retardation film 12 e is formed by coating the glasssubstrate 12 a with the resin material for the retardation film using aspin coating method, etc.

Since this retardation film 12 e can also serve as the stepwise member,it is possible to simplify the manufacturing steps. The stepwise memberis provided to adjust a balance between transmittance in thetransmissive mode and reflectance in the reflective mode and it ispreferable to set the ratio of the cell gap in the reflective region Bto the cell gap in the transmissive region A to approximately 1:2. Torealize this ratio, the thickness of the stepwise member is normallycontrolled.

Then, the reflective film 12 d is formed on the retardation film 12 e.For example, the reflective film 12 d is formed by coating theretardation film 12 e with the material for the reflective film such asaluminum using a sputtering method, etc. Then, the reflective film 12 dand retardation film 12 e are patterned and an opening corresponding tothe transmissive region A is formed. Therefore, the reflective film 12 dis provided on the reflective region B of the glass substrate 12 athrough the retardation film 12 e.

This results in a structure with the retardation film 12 e which isphase difference forming means arranged on the backlight side of thereflective film 12 d which is the reflective member in the reflectiveregion B.

The circularly polarized light plates 13, 14 are circularly polarizedlight plates having polarization directions opposite to each other.Here, suppose the circularly polarized light plate 13 is a rightcircularly polarized light plate and the circularly polarized lightplate 14 is a left circularly polarized light plate. The circularlypolarized light plates 13, 14 can be provided on the glass substrates 12a, 12 b by pasting them onto the outer surfaces of the glass substrates12 a, 12 b.

Then, the operation of the transflective liquid crystal display devicein the above described structure will be explained. Note that theoperation in the reflective mode in which ambient light is used as alight source is the same as that of a normal transflective liquidcrystal display device, and therefore explanations thereof will beomitted.

In the transmissive mode in which the light of the backlight 11 is usedas a light source for the display, the light emitted from the backlight11 in the reflective region B passes through the circularly polarizedlight plate 13. Since the circularly polarized light plate 13 is a rightcircularly polarized light plate, a part of the left circularlypolarized light of the light which has passed through the circularlypolarized light plate 13 is absorbed and becomes the right circularlypolarized light.

When this right circularly polarized light enters the retardation film12 e of the liquid crystal panel 12, the phase of the right circularlypolarized light is delayed by ¼. The light with the phase delay with ¼becomes linearly polarized light and is reflected on the reflective film12 d. The phase of the light reflected on the reflective film 12 d isdelayed by the retardation film 12 e by ¼ again. In this way, thislinearly polarized light becomes right circularly polarized light again.Therefore, the right circularly polarized light passed through theretardation film 12 e, reflected on the reflective film 12 d and passedthrough the retardation film 12 e again becomes the right circularlypolarized light as is. That is, by being reflected on the reflectivefilm 12 d, the right circularly polarized light becomes the leftcircularly polarized light, but since it passes through the retardationfilm 12 e twice, the phase thereof is delayed by 2′¼, and therefore itreturns to the right circularly polarized light.

This right circularly polarized light passes through the circularlypolarized light plate 13 which is the right circularly polarized lightplate as is. Then, the right circularly polarized light is reflected onthe reflective film 11 b and diffused by the diffusing film 11 a. Whenpassing through the diffusing film 11 a, with circular polarizationcanceled, the right circularly polarized light returns to the naturallight as well as the light from the backlight 11. For this reason, thelight reflected on this backlight 11 is added to the light directlyemitted from the backlight 11 in the transmissive region A. That is, thelight from the backlight 11 in the reflective region B whichconventionally used to be wasted without being used can be used in atransmissive mode.

Then, the effect of the present invention will be explained using FIG. 1and FIG. 2. Here, to facilitate an understanding, it is assumed that theamount of light emitted from the backlights 1, 11 is 100 and the arearatio (%) between the reflective region B and transmissive region A isB:A.

In the transflective liquid crystal display device shown in FIG. 1, thelight emitted from the backlight 1 in the reflective region B in atransmissive mode cannot pass through the above described circularlypolarized light plate 3, being wasted. Thus, only the light emitted fromthe backlight 11 in the transmissive region A is used for a display.Therefore, the utilization rate of the light used in the transmissivemode is 50 A %.

On the other hand, in the transflective liquid crystal display deviceaccording to the present invention shown in FIG. 2, the light emittedfrom the backlight 11 in the reflective region B in a transmissive modecan pass through the above described circularly polarized light plate 3,and can thereby be used for a display. Assuming that the reutilizationrate of light is a, the utilization rate of this light is a B %.Furthermore, the utilization rate of the light emitted from thebacklight 11 of the transmissive region A is 50 A % as described above.Therefore, the utilization rate of the light used in the transmissivemode is a B %+50 A %.

Note that the light utilization rate a is a value affected by thereflectance of the reflective film 11 b and the degree of cancellationof circular polarization of the diffusing film 11 a of the backlight 11,and a is small when the reflectance of the reflective film 11 b and thedegree of cancellation of circular polarization of the diffusing film 11a are small.

Thus, the transflective liquid crystal display device according to thisembodiment can effectively use the light emitted from the backlight 11in the reflective region B in a transmissive mode, and therefore whenthe brightness of the panel is kept at the same level, it is possible tosuppress the necessary output of the backlight 11 more than theconventional one. As a result, it is possible to reduce powerconsumption of the backlight 11 and extend the life of the backlight 11.Furthermore, using the output of the backlight 11 at the same level asthat of the conventional one can increase the brightness of the panel.

Furthermore, if the same transmittance as that of the conventional onein a transmissive mode is realized, it is possible to narrow thetransmissive region (opening) A of each pixel, and thereby relativelywiden the reflective region B. As a result, it is possible to increasethe reflectance in the reflective mode and also improve the displayperformance in the reflective mode.

Embodiment 2

This embodiment will describe another example of phase differenceforming means provided in the reflective region of a liquid crystalpanel. This embodiment will describe a case where an in-cell retarder isused for the phase difference forming means.

FIG. 3 a is a sectional view showing another example of phase differenceforming means in a transflective liquid crystal display device accordingto Embodiment 2 of the present invention. Here, in FIG. 3 a, the samemembers as those shown in FIG. 2 are assigned the same referencenumerals.

The retardation film 12 e shown in FIG. 3 a is constructed of anordinary stepwise formation layer 12 f and an in-cell retarder 12 g.This in-cell retarder 12 g can be constructed of a polymer liquidcrystal layer with oriented liquid crystal molecules, etc.

When the retardation film 12 e shown in FIG. 3 a is formed, anorientation film (not shown) made of polyimide, etc., is formed on aglass substrate 12 a first. Then, the orientation film is subjected toorientation processing by rubbing this orientation film. Then, theorientation film is coated with the polymer liquid crystal fororientation. In this way, the in-cell retarder 12 g is formed on theglass substrate 12 a. This makes it possible to form a phase difference.In the present invention, it is desirable to delay phase with ¼, andtherefore it is preferable to control the film thickness and temperatureaccordingly.

Then, the stepwise member 12 f is formed on the in-cell retarder 12 g. Aresin material can be used for the stepwise member 12 f. When thestepwise member 12 f is formed on the in-cell retarder 12 g, the resinmaterial is coated using a spin coating method, etc.

Further, a reflective film 12 d is formed on the retardation film 12 e(stepwise member 12 f) as in the case of Embodiment 1. Then, thereflective film 12 d and retardation film 12 e (stepwise member 12 f andin-cell retarder 12 g) are patterned to form an opening corresponding toa transmissive region A.

Then, the operation of the transflective liquid crystal display devicein the above described structure will be explained. The operation in areflective mode using ambient light as a light source is the same asthat of an ordinary transflective liquid crystal display device, andtherefore explanations thereof will be omitted.

In a transmissive mode, when right circularly polarized light emittedfrom the backlight 11 in a reflective region B and passed through acircularly polarized light plate 13 enters the in-cell retarder 12 g ofthe liquid crystal panel 2, the phase of the right circularly polarizedlight delays with ¼. The light with a phase delay with ¼ becomeslinearly polarized light and is reflected on the reflective film 12 d.The phase of the light reflected on the reflective film 12 d is furtherdelayed with ¼ in the in-cell retarder 12 g again. This causes thislinearly polarized light to return to the right circularly polarizedlight. Therefore, the right circularly polarized light passed throughthe in-cell retarder 12 g, reflected on the reflective film 12 d andpassed through the in-cell retarder 12 g becomes the right circularlypolarized light as is. That is, the right circularly polarized lightbecomes left circularly polarized light by being reflected on thereflective film 12 d, but since it passes through the in-cell retarder12 g twice, the phase thereof is delayed with 2′¼ and the light becomesthe right circularly polarized light. This right circularly polarizedlight is reused as the light source in the transmissive mode as in thecase of Embodiment 1. For this reason, as in the case of Embodiment 1,the light from the backlight 11 in the reflective region B whichconventionally used to be wasted without being used can be used in thetransmissive mode.

Embodiment 3

This embodiment will describe a further example of phase differenceforming means provided in the reflective region of a liquid crystalpanel. This embodiment will describe a case where a retarder outside thesubstrate is used as the phase difference forming means.

FIG. 3 b is a sectional view showing the other example of phasedifference forming means in a transflective liquid crystal displaydevice according to Embodiment 3 of the present invention. Here, in FIG.3 b, the same members as those shown in FIG. 2 are assigned to the samereference numerals.

The phase difference forming means shown in FIG. 3 b is constructed ofan ordinary stepwise formation layer 12 f provided inside the liquidcrystal cell, a retarder 12 h provided outside the liquid crystal cell.This retarder 12 h has a function of delaying phase with, for example, ¼(approximately 100 to 200 nm). This retarder 12 h can be constructed ofa phase difference film and retardation film, etc.

When the phase difference forming means shown in FIG. 3 b is formed, astepwise member 12 f is formed on a main surface of the glass substrate12 a on the liquid crystal cell side (inside the cell) first. When thestepwise member 12 f is formed on the glass substrate 12 a, a resinmaterial, etc., is coated using a spin coating method, etc.

Furthermore, a reflective film 12 d is formed on the stepwise member 12f as in the case of Embodiment 1. Then, the reflective film 12 d andstepwise member 12 f are patterned to form an opening corresponding tothe transmissive region A.

Then, the retarder 12 h is partially formed in the region on the mainsurface opposite to the liquid crystal cell (outside the cell) of theglass substrate 12 a, in which the stepwise member 12 f is formed. Whena phase difference film is used as the retarder 12 h, the phasedifference film is partially pasted to the region corresponding to theregion of the glass substrate 12 a in which the stepwise member 12 f isformed. On the other hand, when the retardation film is used as theretarder 12 h, a resin material is coated using a spin coating method,etc., as in the case of Embodiment 1 and then patterning is performed insuch a way that a retardation film remains in the region correspondingto the formation region of the stepwise member 12 f.

Then, the operation of the transflective liquid crystal display devicein the above described structure will be explained. The operation in areflective mode using ambient light as a light source is the same asthat of an ordinary transflective liquid crystal display device, andtherefore explanations thereof will be omitted.

In a transmissive mode, when right circularly polarized light emittedfrom the backlight 11 in a reflective region B and passed through acircularly polarized light plate 13 enters the retarder 12 h of theliquid crystal panel 2, the phase thereof is delayed with ¼. The lightwith a phase delay with ¼ becomes linearly polarized light and isreflected on the reflective film 12 d. The phase of the light reflectedon the reflective film 12 d is further delayed with ¼ in the retarder 12h again. This causes this linearly polarized light to become the rightcircularly polarized light. Therefore, the right circularly polarizedlight passed through the retarder 12 h, reflected on the reflective film12 d and passed through the retarder 12 h again becomes the rightcircularly polarized light as is. That is, the right circularlypolarized light becomes the left circularly polarized light by beingreflected on the reflective film 12 d, but since it passes through theretarder 12 h twice, the phase thereof is delayed with 2′¼, thusbecoming the right circularly polarized light. This right circularlypolarized light is reused as the light source in the transmissive modeas in the case of Embodiment 1.

For this reason, as in the case of Embodiment 1, the light from thebacklight 11 in the reflective region B which conventionally used to bewasted without being used can be used in the transmissive mode.

In this embodiment, the phase difference forming means is constructed ofthe stepwise member 12 f and retarder 12 h separately, which makes itpossible to reduce the thickness of the retarder 12 h.

The present invention is not limited to Embodiments 1 to 3 above, butcan be implemented modified in various ways. For example, the presentinvention is not limited to materials described in Embodiments 1 to 3above, but can be implemented modified in various ways.

Said embodiments 1 to 3 have described the case where the retardationfilm for delaying phase with ¼ is used, but the retardation film of thepresent invention is not limited to the retardation film for delayingphase with ¼ if the orientation of circularly polarized light can be atleast reversed by allowing the light to pass through the film or layertwice. Furthermore, Embodiments 1 to 3 above have described the casewhere the circularly polarized light plates 13, 14 are pasted to theglass substrates 12 a, 12 b, but the present invention is applicable ifthe circularly polarized light plates 13, 14 are at least arrangedoutside the glass substrates 12 a, 12 b in the liquid crystal panel 12.

As described above, the transflective liquid crystal display device ofthe present invention comprises a pair of circularly polarized lightmembers arranged outside the liquid crystal panel and a backlightarranged outside one circularly polarized light member of the pair ofcircularly polarized light members, wherein the reflective region has areflective member for reflecting ambient light from an opposite side ofbacklight-arranging side in the liquid crystal panel, and the reflectiveregion has phase difference forming means arranged on the backlight sideof the reflective member, and therefore it is possible to reverse thepolarization direction of circularly polarized light from the backlightin the reflective region and allow the light reflected on the reflectivemember to pass through the circularly polarized light member. As aresult, the light from the backlight in the reflective region whichconventionally used to be wasted without being used can be used in atransmissive mode.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a transflective liquid crystaldisplay device used for a cellular phone or PDA (Personal DigitalAssistant), etc.

1. A transflective liquid crystal display device having a liquid crystalpanel in which liquid crystal material is sealed between a pair ofsubstrates faced with each other and in which pixels formed on onesubstrate of said pair of substrates have transmissive regions andreflective regions, comprising: a pair of circularly polarized lightmembers arranged outside said liquid crystal panel; and a backlightarranged outside one circularly polarized light member of said pair ofcircularly polarized light members, wherein said reflective region has areflective member for reflecting ambient light from an opposite side ofbacklight-arranging side in said liquid crystal panel, and saidreflective region has phase difference forming means arranged on thebacklight-arranging side of said reflective member.
 2. The device asclaimed in claim 1, wherein said phase difference forming means has afunction of reversing a direction of circularly polarized light byallowing circularly polarized light to pass therethrough twice.
 3. Thedevice as claimed in claim 1, wherein said phase difference formingmeans is formed on said reflective regions in a main surface inside saidliquid crystal panel on one substrate on the backlight-arranging side ofthe pair of substrates and said reflective member is formed on saidphase difference forming means.
 4. The device as claimed in claim 3,wherein said phase difference forming means is a retardation film fordelaying phase with λ/4.
 5. The device as claimed in claim 1, whereinsaid phase difference forming means also serves as a stepwise member foradjusting a balance between transmittance in said transmissive regionand reflectance in said reflective region.
 6. The device as claimed inclaim 1, wherein said phase difference forming means isorientation-processed polymer liquid crystal layer.
 7. The device asclaimed in claim 6, wherein said polymer liquid crystal layer delaysphase with λ/4.
 8. The device as claimed in claim 1, wherein said phasedifference forming means is formed on said reflective regions in a mainsurface outside said liquid crystal panel on one substrate on thebacklight-arranging side of said pair of substrates.
 9. The device asclaimed in claim 8, wherein said phase difference forming means is aretardation film or a phase difference film for delaying phase with λ/4.